Engine bearing failure analysis.
Diesel engine connecting rod bearing failure.
Bearings fail when the oil film breaks down or when the bearing is overloaded.
At rest the shaft and bearing are in contact.
The oil film is generated by shaft rotation figure b.
Car oriented types tend to try to ignore bearing issues compensating for them by using ever thicker oil and an eye on the gauges instead of just replacing them as necessary.
Also shown is a damaged piston cooler.
Sometimes a fairly new engine can have fatigued connecting rods if it is a rebuilt engine and the mechanic used cheap parts or the wrong parts for the engine.
Excessive idling can result in an oil film that can not support the load needed.
In many cases misassembly will result in premature failure of the bearing.
If a bearing isn t set into place securely lubrication will be insufficient and cause failure.
Pin failure the pin that connects the connecting rod to the piston called the piston pin wrist pin or gudgeon pin gets a lot of wear.
The above pictures show two areas of failure the connecting rod bearing and the cylinder kit.
Typically the big end connects to the crankpin using a plain bearing to reduce friction.
If a connecting rod or main bearing cap is installed in the wrong position or a bearing isn t set into place securely lubrication will be insufficient and cause failure.
Other causes of engine bearing failure.
The small end attaches to the gudgeon pin also called piston pin or wrist pin which can swivel in the piston.
The following are typical assembly errors most often made in the installation of engine bearings.
When a connecting rod or main bearing cap is installed in the wrong position.
Of all the things that can take your engine out bearing failure is one of the most insidious.
Engine bearings depend on a film of oil to keep shaft and bearing surfaces separated figure a.
Engine bearings will not function properly if they are installed incorrectly.
Failures in con rods have been reported in the literature being associated to fatigue overload bending bearing failure improperly adjusted bolts spalling and assembly deficiencies.
However some smaller engines may instead use a rolling element bearing in order to.
Incorrect clearances will result in seizure of the connecting rod bearing.
A connecting rod for an internal combustion engine consists of the big end rod and small end.
The piston cooler if bent can cause a piston to seize and cause the piston pin bearing to fail.
This paper presents the results of a failure analysis investigation conducted in a connecting rod from a diesel engine 18 v four stroke used in.
Careful installation procedures are of course critical in every aspect of engine building careless errors are always expensive.
